It was a night of upsets in the Division I sectional semifinals Thursday, as the fourth-seeded Middleton girls basketball team upended top seed Mukwonago 71-66 and Madison East beat Sun Prairie for the first time in three tries this season, 65-53, to set up an all-Big-Eight showdown in tomorrow afternoon’s sectional finals at Janesville Craig High School.

The East win was an unusual one.

“Sun Prairie had a hold on us for the last 6 years,” Head Coach James Adams said on Tuesday, before the semifinal game.

No longer, apparently.

“If we beat them, it’s a statement,” said East senior Kalea Kruser before the game.

It was an emphatic one.

The Purgolders handcuffed Sun Prairie’s leading scorer, guard Jayda Jansen, who had scored a total of 50 points in Sun Prairie’s two wins over East during the regular season. Adams’ defensive scheme focused on the 5’10” junior, and it worked, as East allowed the Cardinals’ high-power offense only 15 points in the first half and went into the locker room with a 23 point lead.

Sun Prairie mounted a comeback but it was never going to be enough.

The win sets up a clash with another conference rival, Middleton, which split the season series with East, each team winning on the other’s home floor.

The first game, an East win at Middleton, was marred by a postgame social media controversy, in which a Middleton player used her Instagram account to criticize East’s physical style of play and included the remark “”#youregonnaworkforusanyway,” an apparent allusion to the fact that Middleton is mostly white while East is mostly black and Latino.

“After that win, we were very happy that night, but later that night when we found out about the post, we weren’t able to enjoy that win as much because of the post,” said East junior Erin Howard, and Auburn recruit. “We know we have to put that behind us. We still think about it here and there but once we step on the floor, we have to go out there and play.”

Both teams seemed to have put it behind them by February 18, when Middleton came to East and spoiled senior night with a narrow victory.

Middleton Cross Plains Area School District Spokesman Perry Hibner noted that East coach Adams, who works at Middleton High School, addressed the crowds before that game, exhorting everyone to stay positive and focus on the game.

“He spoke for all of about 45 seconds but that message was really taken to heart,” Hibner said. “Hopefully that same message will carry on through Saturday’s game.”

Hibner said that second meeting between Middleton and East was “a great game that was played without controversy. There wasn’t anything in that game other than two teams playing hard.”

Hibner said no special communication had been sent or given to Middleton fans in preparation for the sectional final.

“In reality that sort of communication happened before the second game at East,” he said.

Still, Saturday’s game will take place in an emotional and electric atmosphere, with a berth in the state tournament on the line — and allegations of racially insensitive behavior on the part of Middleton students and parents hovering in the background.

Neither team was available for comment Friday, but several East players already made their prediction earlier in the week.

“If we win on Thursday,” said Howard before practice on Tuesday, “I don’t feel like we lose again this season.”